Methods and apparatuses consistent with example embodiments relate to memory, and more particularly to semiconductor memory devices, memory systems and methods of operating semiconductor memory devices.
Semiconductor memory devices may be classified into non-volatile memory devices, such as flash memory devices, and volatile memory devices, such as Dynamic random-access memories (DRAMs). High speed operation and cost efficiency of DRAMs make it possible for DRAMs to be used for system memories. Bit errors of memory cells in DRAMs have increased and DRAM yield has decreased due to continued size reduction in fabrication design rule of DRAMs. Therefore, there is a need for credibility of the semiconductor memory device.